This invention relates to an electric motor and in particular, to a miniature electric motor with a combined bearing cover/thrust plate.
Small electric motors are very common and are often used with pinions fitted to the output shaft. Usually, such motors will have a thrust bearing of some form to limit the axial movement of the shaft. However, often the pinion is fitted to the output shaft after the motor has been fully assembled by the purchaser of the motor. As a result, the thrust bearing is damaged when the pinion is fitted due to the relatively large force required to press the pinion on to the shaft which is bearing directly onto the thrust bearing.
One solution to this problem is to use stronger thrust plates but while this reduces the damage to the thrust plate, it does not eliminate the damage and it does add significantly to the cost of the motor. Alternatively, the force required to fit the pinion can be reduced but this can lead to other problems such as loose pinions.
Hence, there is a need for a thrust plate which can avoid being damaged during fitting of a pinion to the output shaft of a miniature electric motor.
Accordingly, the present invention provides a thrust cap for an electric motor comprising: a thrust cap body; a thrust bearing surface supported by the body; and securing means for securing the thrust cap body to the electric motor wherein the thrust bearing surface is sprung and arranged to be in continuous contact with an end of a shaft of the motor to urge the shaft axially away from the thrust bearing cap.
The present invention also provides an electric motor incorporating such a thrust cap.
Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings.